Magnetic ore separator



March 11, 1952 L. DREYUS 2,589,065

MAGNETIC ORE SEPARATOR Filed March 6, 1948 vB/WW Patented Mar. 11, 1952 MAGNETIC ORE SEPARATOR- Ludwig Dreyfus, Vasteras, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a Swedish corporation Application March 6, 1948, Serial No. 13,457 In `Sweden March 12, 1947 2 Claims. (Cl. 209-226) For separating magnetic pulverulent material from non-magnetic material, it has been previously proposed to employ a unidirectional magnetic flux whcih is substantially constant over a large pole surface in combination with a superposed alternating flux having a several times smaller pole pitch, intended to effect an agitation of the material attracted by the unidirectional ilux and thereby a more elcient separation of the non-magnetic material from the magnetic material. This agitation is intended to be created by the resultant flux varying in strength. In the hitherto employed separators of this kind, however, the alternating flux has had a much smaller pole pitch than the unidirectional flux, and the result hereof has been, that at such instants, when the alternating flux is zero, there will be no agitation of the material.

According to the present invention, the unidirectional ux and the alternating flux have equal pole pitches and therefore will combine to a resultant ilux which varies comparatively little in strength but oscillates constantly between different directions and therefore causes a very eilicient agitation of the material, as set forth in the following description.

In the accompanying drawing, Fig. 1 shows a complete separator according to the present invention in a cross section, while Fig. 2 shows a detail of a modified form of the invention in a corresponding section.

Referring to Fig. 1, the magnetic system is surrounded by a diaphragm 4 in the shape of a drum or a band, towards which the magnetic material is attracted.

The material is fed into the separatorat the point A, and the magnetic particles are rst attracted by simple direct current poles 5, 6. Later on, when the side of the diaphragm to which the material adheres is turned downwards, the said material is attracted by composite poles 1. These have direct current windings 8 but also alternating current windings 9 placed in slots in the pole surfaces. The lines of force of the direct current flux are full-drawnl while the lines of force of the alternating current flux are dotted. The polarity of the different poles is preferably such that the direct current and the alternating current lines of force intersect under substantially right angles, whereby a column of magnetic grains which occupies the direction of the direct current flux, is perpetually subjected to a vigorous agitation in a direction substantially perpendicular thereto by the alternating current flux. By suitably proportioning the two fluxes against each other, it has been found possible to reduce the content of non-magnetic material in the manetic material to about five per cent, while at the same time only about one per cent of the magnetic material accompanies the non-magnetic material and thus is lost. It has not been possible to obtain similar results by earlier combinations of different fluxes for the separation. The non-magnetic material removed by the agitation falls down from practically the Whole bottom portion of the diaphragm, while the magnetic material is discharged at B, where the diaphragm leaves the magnetic eld.

Fig. 2 shows a portion of the magnetic system having slots I which contain a direct current winding 2 as well as an alternating current winding 3. The pole surfaces of the said system may lie in one plane, as shown, or follow a curved surface, as in Fig. 1. In front of the pole surfaces there is a diaphragm 4, which also may be plane or curved, and which in the latter case may form a drum. The direction of motion of the said diaphragm may be that of the arrow or perpendicular to the plane of the drawing. The lines of force of the direct current ux are still shown as full-drawn lines and the lines of force of the alternating current ux as dotted lines. Also here, the said lines of force intersect under nearly right angles, whence the operation will be substantially the same as in Fig. 1.

I claim as my invention:

l. Magnetic ore separator comprising magnetic pole pieces, windings adapted to create a unidirectional fiux and a superimposed alternating ilux having pole pitches through said pole pieces, the magnetic axes of said uxes being mutually displaced in space by a substantial angle, a nonmagnetic diaphragm capable of moving in front of said pole pieces, and means for feeding a pulverulent material on to said diaphragm.

2. Magnetic ore separator comprising magnetic pole pieces, windings adapted to create a unidirectional flux and an alternating flux having equal pole pitches through said pole pieces, the magnetic axes of said fluxes being mutually displaced in space by half a pole pitch, a non-magnetic diaphragm capable of moving in front of said pole pieces, and means for feeding a Dulverulent material on to said diaphragm.

LUDWIG DREYFUS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,218,916 Weatherby Mar. 13, 1917 FOREIGN PATENTS Number Country Date 600,048 Germany July 13, 1934 

